Impact wrench



F. H. THOMAS Dec. 18, 1951 IMPACT WRENCH Filed oct. 25, 19.46

Patented Dec. 18, 951 2 1; f 5

- UNITED STATES rATENT OFFICE:A

Floyd H. Thomas, Milan, Pa.,assignor to Ingersoll-Rand Company, New York,` Nk. Y., a corporation of New Jersey Application october 25, 1946, serial No. 705,761

. Claims. (Cl. 1918-305) l 1 lhis invention relates to wrenches and particularly to that type of wrench in` which hammer blows are delivered when the torque resistance exceeds some predetermined amount.

YOne of the objects kof the invention is to provide a, sturdy and reliable wrench of this character. Y

In tools of this character there is usually provided a spindle with anvil faces which are adapted to be struck by a hammering element. In some types that have been used heretofore there is a tendency for the hammer element to strike a glancing blow which is apt to cause less kthan the full power Vof the impact to be delivered to theanvil and furthermore is apt to chip the face ofthe anvil. It is a further object of this invention to obviate these said defects.

Other objects and advantagesof the inventionwill be in part obvious and in part pointed out hereinafter. l Y

In thedrawing which illustrates a preferred embodiment of the invention and in which similar reference characters refer to similar parts,l

Figure 1 is a longitudinal section throughl the impacting portion of a wrench constructed in accordance with the invention, only aportion of the .driving motor Vbeing indicated,

Figure 2 is a cross-section through the wrench taken along the line 2-2of Figure 1 looking the-direction of the arrows;

ggFlgure 3 is a cross-section along the line 3,-3

"of .Figure 1 looking in the direction `of the arrows;

vFigure 4 is a section through the spindle and hammer elements of the wrench taken along the line 4-4 of Figure 1 looking in the direction of` the arrows, and

f Figure Y5 is a section through a part of the spindle and hammer elements taken along the line 5-5 of Figure 2 looking in the direction of the arrows.

Referring to the drawings there is illustrated a wrench of the impacting type including a motor portion I0 of which only a part is shown having a drive shaft II extending forwardly into the hammer casing I2.' Within the hammer casing isprovided a spindle I3suitably journaled in a bearing shell I4 at the forward endV of ythe housing andiprovided witha square end I5 adapted to receive a suitable socket wrench I6. A rearward portion of the spindle yI3 is provided Withl a bore-I1 cooperating with the reduced end portion I8 of the drive shaft I-I to maintainalignment of the spindles.l longitudinal movement of the spindle I3 within the housing I2 is restricted f 2 by a collar I9 formed integrally with the spindle I3.-

Spindle I3 is adapted to be driven by the drive shaft I I of motor I0 through the medium of a hammer element 2D encircling the spindle I3 and guided at its forward end by the collar I9. An end face 2| is provided to bear against the bearing member I4. The hammer element 20 is of considerable mass with respect to the spindle I3 and is adapted to be driven at high speed bythe shaft II.

Suitable means for clutching the hammer 20 to the spindle I3 is provided including anvil portions 22 formed on spindle I3 and dogs 23, 24, 25 and 26 rotatably mounted in bores 21, 28, 29 and 30, respectively, formed longitudinally in the interior of the hammer 26 and parallel to the axis of spindle I3. The dogs 23, 24, 25 and 26 are in. the form of pawls which are adapted to engage the faces 3l of the anvils 22 upon rotation in a. clockwise direction (Figure 4) and the faces 32 of anvils 22 upon rotation of the hammer in a counterclockwise direction,

The dogs are interconnected in pairs so as toy rotate in their respective bores in the same di, rection. Thus the dogs 23 and 24 are providedy at; their ends with hexagonal ends 33 and `34, respectively, upon which are mounted spur gears 35Vand 36, respectively, andan interconnecting gear 3 1 meshing with gears 35 and 36 is provided. Likewise upon hexagonal ends 38 and 39 are mounted gears 40 and 4I, respectively, for interconnecting dogs 25 and 26 respectively, through the medium of a gear 42. Gears 31 and 42 are rotatably mounted on studs 43 and 44 respectively, projecting from the upper end of the hammer 20. A plate 45 is provided as a means to hold the gears 35, 36, 31, 40, 4I and 42 in place. The plate 45 is provided with apertures 46 through which the studs 43 and 44 pass and bores 4'! acting as bearings for the dogs 23, 24, 25 and 26. The plate 45 lies on the inner face 48 of the hammer element 20 and is fastened thereto by screws 49.

Driving connection between the shaft II and the hammer element 20 consists of a dog l5|) mounted on a squared portion 5I of shaft I I and provided with hook-like projections 52 adapted to'` engage cams 53 mounted on the hexagonal? Si. Thus assuming that the hammer element 2D is relatively stationary, rotation of the shaft II in a counter-clockwise direction rotates the dogs 24 and 25 to disengage the anvil faces 32 while the dogs 23 and 26 are moved into the path of 5 the anvil faces 3|. Rotation of the shaft II in a clockwise direction producesntheropposite effect--that is fte say', dogs 24 and 25are moved into the path of the anvil faces 32 and dogs'2I5 and 21 are moved out of the path of the anvilv faces 3|. However, as the hammer 20' rotatesv with respect to the spindle I3 the forwartdogis moved back into the path of the approaching anvil face by the action of thev anvil 2 :2 engaging the trailing dog which, through the medium" of the interconnection gears 31 and 42, causes the leading dogs to move inwardlyintothepathoff.. the approaching anvil face. Y

I may illustrate the operation of the devicek as applied to the tightening of a nut 60 upon a bo'ltSl. AAssuming'that the socket wrench I6 has been placed on the nut te, and the driving motor has'been started so that the shaft II 'turns in a clockwise direction (Figures 2, 3, 4) the-shaft; through the dogi` and 'cams 53, rotates thehammer element 23"? and the dogs 23, 24,255 andifZI as'fa unit to turn the spindle lfagainstY slight resistance. When the resist-ance of! nut 60 to turning becomes substantial, spindle I3 will stop rotation offthe hammer element 20 whereupon the pressure of the hook-like projections '52 against the cams 53 tends to rotate the dogs 23 and 26 to disengage the faces 3I ofV the spindie I3, permitting Vrotation of the driving motor andthe hammer element 2li-Without resistance 35 and at ar` resulting high speed. However, simultaneous withv the disengagement of dogs 23j`and- 26'; dogs 2'II; and 25 Will'have been rotated in@ wardly'A sothat'they Will'vbe engaged uponA rota-- tion of hammer 23 by the anvils 22. Upon such 4'" engagement the dogs 23 and 26 are again movedA back inwardly so that their ends willV strike against the faces 3i with a'blow at high velocity' andY resulting in hammering of the spindle I3 to drive'the lnutEil, This'impacting is repeated as long as the driving motor yis maintained inoperation. f `v(lpon-'reversingv of the driving motorr the dogs,A` 2,4 and l25 will impactrthe faces-532todriveth spindle i3 in aV counter-'clockwise directionY andv pawls 2-`and 2 7 act as thev means forresto'r dogs925-`anzl` 214-, respectively, to theY i'riiillac'tiigl positions. Y Thus` by the above construction are accom-'-V p'lvished4 arriongothersl the objeot above referred "'Ijclaim; l 1. An impact' wrench andthe like comprising adriving; motor, aY tool` receiving spindle p rovided with anvil faces, aJ rotatable hammer-el'e ment, a driving dog pivotally mounted on,V said" hammer element adapted' to transmitv the-rota@Y tional energy of said hammer to said anvil faces; ar second ,dog separately mounted on said harrunferl element, inter-'connecting' meansbetween said fidarti ,mei/eene offzaid dogs, into the' path'of Saidlanvilr faces andi ,the` other dog Outf Seid" path simultaneously, the means to transmit drive-v irig face'from Said` motor to said dogs and tendl in" to holdv one of said-*dogs out ofv the-path of said anv'iiffaces.

2; iinpactwrench-and thel likej comprising a driving motor, a tool receiving Vspindleprl vid d) with anvil: faces', a rotatable lhav'mrner' velement, a pair of dogs each separately mounted on said hammer element on an axis parallel to the axis of said spindle and adapted to transmit the rotational energy of said hammer to said anvil faces, means on the dogs for transmitting rotary motion thereto, inter-connecting means be- .,.tlee .rteid meaesitomeverone 0f Said dogs-into thepath of said anvilfffaces and the other dog" out' of" said path simultaneously, and

means to transmit driving force from said motor to' said dogs and tending to hold one of said dogs outof, the path of said anvil faces.

3, An impact wrench and the like comprising Y' ajdrivingf motor,;-afftool receiving spindle providediwithl' Y yrvilfaces, a rotatable hammer element, a pair of "dogs each pivotally mounted on said; hammer-element adapted to transmit the rotationalenergy of said hammer to said anvil faces, gears on said dogs, an inter-connecting gear between 'first said gears to move one of said dog-s; intof theA path of! saidr anvil faces andi'vthe otherl dog outlofi-'said path simultaneously, and meansto-transmit driving force vfrom said motor" to said-dogsandtending to-hold one of said dogsoutLoff-tli'e---path efsaid anvil facesfincludir'ig armsf onsaid dogs-projectingA inwardly toward the spindle and an element, rotatable by saiddriving motorit'oengagesaid arms; Y

4. Animpaotwrench and the like comprising a` drivingl motor,` aV tool-'- receiving spindle p'ro'r vided withanvill faces, avrotatablewhammer element, a pair ofclogsV eaclr pivotally mounted onl said hammer element on" axis parallel to the axis of A`saidspindle and'adapted to transmit-the rotationalenergyof said hammer toV said anvil faces,=a gears-traininter-connecting saiddogs toI move one of said dogs into thepath of said an-v vill facesand the. otherl dog out Aof saidv path simultaneously, andv means to transmit driving force from said motor to said dogs" and tending-r tohold/ one oflsaid'- dogsout of the path of said anvilfaces-including armsY on said dogsj pro--V jecting inwardly toward-,the spindle and anellement rotatableby said driving motor to engage said arms;v Y M v 5. An -impact'wrenchandthelike comprisingv ardriving motor-,- a= tool receivingspindle 15110;" vided'withanvilbfaces; a' -rotatable-hammer element, 'af pair of'dogs` eachn pivotal'lymountedonj said hammer elementV` 4 adaptedto transmitthel rotational energy o f Asaid hammer-11 to' said--anvil faces;v inter-connecting-means-between said? 'M' to move one of said dogs into the path 0f zSeidL anvil faces, andi theroth'erdogr out of sai'df'riathY sirnultaneously,andmeans:` to' transmit drivin'gi force@` fromsai'd motorto said dogs'- and" coni-Vf stantly tending to hold one of said-'dogsoutlo'fi amai.@rameneraces; the, @memoriam mg into @enact wirr; the. spiadier'immediare1y-. prior-'toi tlr'efrst dog'f'striking said4 faces arid ing, actuated,V by said spindle tomoveV theiirst dog into the path ofgthe, anvilj faces.

errant,

following references; airerof IfeQOldf in the lie ofthisipat f UNITE Drsfrnfrns Prlfrfrzrrr si f Number 'Name i Date 117443121.. DQMQQYQ-- Sept/26119.39; 2722851639: Amtsberg 23433596`v 

